Amides of 2,4,6-trialkyl-3-hydroxy-phenylalkanoic acids

ABSTRACT

Ester and amides having the formula ##STR1## wherein R, R 1  and R 2  are independently lower alkyl or cycloalkyl groups, R 3  is hydrogen, alkyl, cycloalkyl, alkylene, phenyl, phenyl substituted by alkyl groups, alkylthioethyl, thiobis-alkylene, alkyleneoxyalkylene, polyoxyalkylene or a polyvalent cyclic or acyclic hydrocarbon radical, R 4  is hydrogen, lower alkyl, cycloalkyl, R 5  is hydrogen, alkyl, phenyl, phenyl subsstituted by alkyl groups, alkylene, a polyvalent cyclic or acyclic hydrocarbon radical or alkyleneoxyalkylene, A is lower alkylene, m is 1 to 4 and n is 1 to 6.

This application is a divisional of copending application Ser. No.494,156, filed Aug. 2, 1974, now U.S. Pat. No. 3,988,363, issued Oct.26, 1976, which in turn is a continuation-in-part of application, Ser.No. 400,603, filed Sept. 25, 1973, now abandoned.

The esters are prepared by usual esterification procedures from asuitable alcohol and an acid of the formula III ##STR2## or an aicdhalide or acid anhydride thereof. The higher alkyl esters can also beprepared from the lower alkyl ester, especially the methyl ester, bytransesterification with a higher alkanol or polyol.

The amides are prepared by usual amidation procedures by reacting acarboxylic acid of formula III, an acid chloride, anhydride or a loweralkyl ester thereof with the appropriate amine.

The nitriles corresponding to acids of formula III are prepared as wellas some malonate esters derived having the formula V. ##STR3##

The compounds are useful as stabilizers of organic materials, especiallypolyolefins, which deteriorate upon exposure to light and heat.

DETAILED DISCLOSURE

This invention pertains to esters and amides of2,4,6-trialkyl-3-hydroxyphenylalkanoic acids and to organic materialsnormally subject to oxidative, thermal and UV light deteriorationstabilized with said ester and amide compounds. More specifically, thecompounds of this invention are those having the formula I or II:##STR4## wherein

R, R¹ and R² are independently lower alkyl of 1 to 8 carbon atoms or acycloalkyl of 5 to 6 carbon atoms, provided that there are no more than2 cycloalkyl groups,

R³ is hydrogen, alkyl of 1 to 24 carbon atoms, cycloalkyl of 5 to 6carbon atoms, phenyl, phenyl substituted with alkyl groups, said alkylgroups having 1 to 18 carbon atoms, alkylthioethyl of 4 to 27 atoms inthe chain, thiobis-alkylene of 5 to 9 atoms in the chain, alkylene of 2to 12 carbon atoms, cycloalkylene of 5 to 8 carbon atoms, alkylene of 7to 10 carbon atoms containing a cycloalkane group in the chain,alkyleneoxyalkylene of 5 to 9 atoms in the chain, polyoxyalkylene of 8to 101 atoms, or a polyvalent acyclic or cyclic hydrocarbon radical of 3to 10 carbon atoms,

R⁴ is hydrogen, lower alkyl of 1 to 8 carbon atoms, cycloalkyl of 5 to 6carbon atoms, R⁴ and R⁵ together form a piperazinyl ring incorporatingboth nitrogen atoms when m is 2, or the group ##STR5##

R⁵ is hydrogen, alkyl of 1 to 24 carbon atoms, phenyl, phenylsubstituted with alkyl groups, said alkyl groups having 1 to 18 carbonatoms, alkylene of 2 to 12 carbon atoms, a polyvalent cyclic or acyclichydrocarbon radical of 3 to 8 carbon atoms or alkyleneoxyalkylene of 5to 9 atoms in the chain,

A is a straight or branched lower alkylene having 1 to 8 carbon atoms ora 1,1-alkylidene of 2 to 8 carbon atoms,

m is an integer of 1 to 4, and

n is an integer of 1 to 6.

The R, R¹ and R² groups can be straight or branched lower alkyl groupshaving 1 to 8 carbon atoms as, for example, methyl, ethyl, propyl,butyl, amyl, heptyl or octyl. R, R¹ and R² can be cycloalkyl of 5 to 6carbon atoms such as cyclopentyl or cyclohexyl. Preferably R is abranched alkyl group of 3 to 8 carbon atoms such as isopropyl,sec-butyl, tert-butyl, sec- and tert-amyl, sec- and tert-hexyl, sec- andtert-heptyl or sec- and tert-octyl, and most preferably a tert-butylgroup. R¹ and R² are preferably an alkyl group having 1 to 3 carbonatoms such as methyl, ethyl or n-propyl and most preferably the methylgroup.

The R³ group can be alkyl of 1 to 24 carbon atoms such as methyl,n-butyl, n-octyl, n-dodecyl, n-octadecyl or n-tetracosanyl. PreferablyR³ is an alkyl group of 1 to 18 carbon atoms such as n-dodecyl orn-octadecyl.

The R³ group also is cycloalkyl of 5 to 6 carbon atoms, preferablycyclohexyl.

R³ is also phenyl or phenyl substituted with alkyl groups, said alkylgroups having 1 to 18 carbon atoms. The substituents may be methyl,isopropyl, tert-butyl and tert-octyl. Substitution in the ortho or parapositions of the phenyl ring is especially preferred. Preferably R³ isphenyl substituted with alkyl groups having 1 to 12 carbon atoms andmost preferably 1 to 8 carbon atoms such as two tert-butyl groups.

R³ can also be alkylthioethyl of 4 to 27 atoms in the chain and havingthe general structure --CH₂ CH₂ SR⁰ where R⁰ is alkyl of 1 to 24 carbonatoms such as n-octyl, n-dodecyl, n-octadecyl and n-tetracosanyl,preferably R³ is alkylthioethyl of 5 to 21 atoms in the chain where R⁰is 2 to 18 carbon atoms.

Where n is 2, R³ is also alkylene of 2 to 12 carbon atoms such asethylene, tertramethylene, 2,2-di-methylpropylene, hexamethylene,octamethylene or dodecamethylene. Preferably R³ is alkylene of 2 to 8carbon atoms and most preferably 2 to 6 carbon atoms.

R³ can also be thiobis-alkylene of 5 to 9 atoms in the chain such asthiodiethylene and thiodibutylene, preferably R³ is thiodiethylene.

R³ is cycloalkylene of 5 to 8 carbon atoms such as 1,3-cyclopentanediyl,1,4-cyclohexanediyl and 2,2,4,4-tetramethyl-1,3-cyclobutanediyl.Preferably R³ is 2,2,4,4-tetramethyl-1,3-cyclobutanediyl.

R³ can also be alkylene of 7 to 10 carbon atoms containing a cycloalkanegroup in the chain such as 1,4-cyclohexanedimethylene and1,5-cyclooctanedimethylene. Preferably R³ is 1,4-cyclohexanedimethylene.

R³ is also alkyleneoxyalkylene of 5 to 9 atoms in the chain such asoxydiethylene, oxydibutylene and oxydi(1,2-propylene). Preferably R³ isoxydiethylene.

R³ can also be polyoxyalkylene of 8 to 101 atoms having the generalstructure --R^(oo) (OR^(oo))_(h) --where R^(oo) is a straight orbranched lower alkylene of 2 to 4 carbon atoms and h is 2 to 33. R^(oo)is ethylene, 1,2-propylene, 1,2-butylene and tetramethylene. PreferablyR³ is polyoxyalkylene of 8 to 11 atoms where R^(oo) is ethylene and h is2 to 3. Most preferably R³ is polyoxyethylene of 8 atoms in the chain.

Where n is 3 to 6, R³ is a polyvalent cyclic or acrylic hydrocarbonradical of 3 to 10 carbon atoms such as 1,2,3-propanetriyl,neopentanetriyl, neopentanetetrayl, 2,2-dimethyl-1,2,2-butanetriyl,2,2-diemthyl-1,2,2-pentanetriyl, 1,2,3,4,5,6-cyclohexanehexayl or1,2,3,4,5,6-hexanehexayl. Preferably R³ is a polyvalent acyclichydrocarbon radical of 3 to 7 carbon atoms and most preferably of 5 to 7carbon atoms.

R⁴ is hydrogen or lower alkyl of 1 to 8 carbon atoms such as methyl,ethyl, butyl, and octyl. Preferably R⁴ is hydrogen or lower alkyl of 1to 4 carbon atoms. Most preferably R⁴ is hydrogen or methyl. R⁴ is alsocycloalkyl of 5 to 6 carbon atoms, preferably cyclohexyl.

Where m is 2, R⁴ can be the group ##STR6## when diethylene triamine ortriethylene tetramine are used in the preparation of the amides offormula II.

When m is 2 and R⁴ and R⁵ together form a piperazinyl ring with thenitrogen atoms of formula II, the amide stabilizers of this inventionhave the structure ##STR7##

R⁵ can be alkyl of 1 to 24 carbon atoms such as methyl, octyl, n-dodecylor n-tetracosanyl, preferably of 1 to 18 carbon atoms such asn-octadecyl.

R⁵ is also phenyl or phenyl substituted with alkyl groups, said alkylgroups having 1 to 18 carbon atoms. The substituents may be methyl,isopropyl, tert-butyl and tert-octyl with substitution preferably in theortho or para positions of the phenyl ring.

Where m is 2, R⁵ is alkylene or 2 to 18 carbon atoms such as ethylene,octamethylene and octadecamethylene. Preferably R⁵ is alkylene of 2 to12 carbon atoms such as ethylene, hexamethylene and dodecamethylene.

R⁵ can also be alkyleneoxyalkylene of 5 to 9 atoms in the chain such asoxydiethylene, oxydibutylene and oxydi(1,2-propylene). Preferably R⁵ isoxydiethylene.

Where m is 3 to 4, R⁵ is a polyvalent cyclic or acyclic hydrocarbonradical of 3 to 8 carbon atoms such as neopentanetetrayl,neopentanetriyl, 1,2,3-propanetriyl and1,4-dimethylcyclohexan-1,1,4,4-tetrayl.

A is a straight or branched lower alkylene of 1 to 8 carbon atoms suchas methylene, ethylene, trimethylene, 1,2-propylene and 1,2-octylene. Ais also a 1,1-alkylidene group of 2 to 8 carbon atoms such asethylidene, 1,1-n-butylidene and 1,1-n-octylidene. Preferably A is astriaght chain alkylene of 1 to 3 carbon atoms, that is, methylene,ethylene and trimethylene, and most preferably is methylene or ethylene.

The integer m is 1 to 4 and preferably is 1 to 2.

The integer n is 1 to 6 and preferably is 1 to 4.

The ester stabilizers of this invention are prepared via usualesterification procedures from a suitable alcohol or polyol, alkylsubstituted phenol, or polyhydric phenol and an acid of formula III##STR8## or an acid halide or acid anhydride thereof. Aryl esters areespecially conveniently made by reaction of the acid halide withhydroxyaryl compounds, for example, phenol, alkyl substituted phenols,polyhydric phenols, naphthols, etc.

The higher alkyl esters are prepared from the lower alkyl ester,especially the methyl ester of the above represented compounds, bytransesterification with a higher alkanol or polyol.

A further embodiment of this invention are nitriles of the formula IV##STR9##

Compounds of formula IV are stabilizers and are also intermediates forconversion to carboxylic acids of formula III. For example, carboxylicacids of formula III, where A is methylene or 1,1-alkylidene of 2 to 8carbon atoms, are readily prepared from IV by hydrolysis. Where A isethylene, the carboxylic acid of formula III is also prepared asoutlined in the following equation; ##STR10## where X is chlorine orbromine and R⁶ is hydrogen or lower alkyl of 1 to 7 carbon atoms.2,4,6-Trialkyl-3-halomethylphenols, such as6-tert.-butyl-3-chloromethyl-2,4-dimethylphenol, are prepared byreaction of hydrogen halide and formaldehyde and the appropriatestarting phenol following procedures described by Wegler et al (Makr.Chem. 9,22 (1952).

Where A is a substituted methylene, the carboxylic acid of formula IIIis prepared conveniently by the halomethylation reaction using a2,4,6-trialkylphenol, hydrogen chloride or bromide and the appropriatealdehyde R⁶ CHO. The starting phenols employed in the preparation of thestabilizers of this invention are commercially available or prepared byknown methods. Of particular interest are phenols which have branchedalkyls or cycloalkyls in an ortho position to the OH of the phenyl ring.Thus, for example the preparation of the following is described in thefollowing references, all of them being prepared by alkylation orcycloalkylation reactions.

6-tert-butyl-2,4-dimethylphenol and 6-cyclohexyl-2,4-dimethylphenol --G. Parc, Revue Inst. Franc. Vol XV, page 689 (1960)

6-(2-methylcyclohexyl)-2,4-dimethylphenol -- Lambert and Williams, U.S.Pat. No. 2,839,493 (June 17, 1958)

6-sec. octyl-2,4-dimethylphenol -- S. A. Dmitrier et al Khim. Technol.Topl. Masel 12 (3),12-16 (1967)

6-(1,1,2-trimethylpropyl)-2,4-diemthylphenol -- Gura et al, Zh. Organ.Khim. 1 (6),1055-7 (1965)

6-isopropyl-2,4-dimethylphenol -- Demerseman et al, Bull, Soc. Chim.France 1962, 1700-5.

The amides of this invention are prepared by known procedures forexample, by reacting the carboxylic acid of formula II or an acidchloride or anhydride thereof with the appropriate amine. The higheralkanamides can also be prepared from the lower alkyl esters of the acidof formula III by known amidation procedures.

A further embodiment of this invention are trialkyl substitutedhydroxphenylalkylene malonate esters of the formula V ##STR11## wherein

R, R¹, R² and R³ are as previously defined,

n is 1 or 2, with the additional proviso that R⁷ is hydrogen when p is 1and R⁷ is nil when p is 2.

The compounds of this invention are stabilizers of organic materialnormally subject to thermal and oxidative deterioration. Materials whichare thus stabilized include synthetic organic polymeric substances suchas vinyl resins formed from the polymerization of vinyl halides or fromthe copolymerization of vinyl halides with unsaturated polymerizablecompounds, e.g., vinyl esters, α,β-unsaturated ketones, α,β-unsaturatedaldehydes and unsaturated hydrocarbons such as butadienes and styrene;poly-α-olefins such as polyethylene, polypropylene, polybutyleneincluding copolymers of α-olefins such as ethylene/propylene copolymerdienes such as polybutadiene, polyisoprene, and the like, includingcopolymers with other monomers; polyurethanes and polyamides such aspolyhexamethylene adipamide and polycaprolactam; polyesters such aspolyethylene terephthalates; polycarbonates; polyacetals such aspolyethylene terephthalate polyacetal; polystyrene, polyethylene oxide;polyphenylene oxide and copolymers; and copolymers such as those of highimpact polystyrene and those formed by the copolymerization ofacrylonitrile, butadiene and/or styrene; natural and synthetic rubberssuch as ethylene/propylene/diene copolymer (EPDM) and chlorinatedrubber.

Other materials which can be stabilized by the compounds of the presentinvention include lubricating oil of the aliphatic ester type, i.e.,di(2-ethylene azelate and other synthetic ester lubricants,pentaerythritol tetracaproate, and the like; animal and vegetablederived oils, e.g., linseed oil, fat, tallow, lard, peanut oil, codliver oil, castor oil, palm oil, corn oil, cottonseed oil, and the like;hydrocarbon materials such as gasoline, mineral oil, fuel oil, dryingoil, cutting fluids, waxes, resins, and the like, salts of fatty acidssuch as soaps and the like; and alkylene glycols, e.g.,β-methoxyethylene glycol, methoxytriethylene glycol, triethylene glycol,octaethylene glycol, dibutylene glycol, dipropylene glycol and the like.

The substrates of particular importance are olefin polymers such aspolyethylene and polypropylene. Polypropylene is especially wellstabilized with the compounds of this invention.

In general, the stabilizers of this invention are employed from about0.01 to about 5% by weight of the stabilized composition, although thiswill vary with the particular substrate and application. An advantageousrange is from about 0.05 to about 2% and especially from 0.1 to about1%.

For addition to polymeric substrates, the stabilizers can be blendedbefore polymerization or after polymerization, during the usualprocessing operations, for example, by hot-milling, the compositionsthen being extruded, pressed, or the like into films, fibers, filaments,hollow spheres and the like. The heat stabilizing properties of thesecompounds advantageously stabilize the polymer against degradationduring such processing at the high temperature generally encountered.The stabilizers can also be dissolved in suitable solvents and sprayedon the surface of films, fabrics, filaments or the like to provideeffective stabilization.

These compounds can also be used in combination with other additivessuch as sulfur-containing esters, e.g., distearyl β-thiodipropionate(DSTDP), dilauryl β-thiodipropionate (DLTDP), in an amount of from 0.01to 2% by weight of the organic material, and the like, pourpointdepressants, corrosion and rust inhibitors, dispersing agents,emulsifiers, antifoaming agents, carbon black, accelerators and otherchemicals used in rubber compounding, plasticizers, color stabilizers,di- and tri-alkyl- and alkylphenylphosphites, heat stabilizers,untraviolet light stabilizers, antiozonants, surface active agents,fillers, dyes, pigments, metal chelating agents, dyesites and the like.Often combinations such as these, particularly the sulfur-containingesters, the phosphites and/or the ultraviolet light stabilizers willproduce superior results in certain applications to those expected bythe properties of the individual components.

The following formula represents co-stabilizers which are in certaininstances very useful in combination with the stabilizers of thisinvention: ##STR12## wherein R is an alkyl group having from 6 to 24carbon atoms; and n is an integer from 1 to 6. Especially usefulcompounds of this type are dilauryl β-thiodipropionate and distearylβ-thiodipropionate. The above co-stabilizers are used in the amount offrom 0.01 to 2% by weight of the organic material, and preferably from0.1 to 1%.

The stabilizers of this invention are particularly useful in protectingpolymer compositions subjected to high temperature processing as well asend uses involving elevated temperatures. Polymer compositionscontaining these stabilizers are resistant to discoloration.

In addition to the above noted additives that can be employed incombination with the compounds of this invention, it is often especiallyadvantageous to employ also light stabilizers. The light stabilizers areused in the amount of from 0.01 to 5% by weight of the organic material,and preferably from 0.1 to 1%. Illustrative examples of lightstabilizers are listed below.

UV-absorbers and light protection agents

2-(2'-hydroxyphenyl)-benztriazoles, such as, for example, the5'-methyl-, 3',5'-di-tert.-butyl-,5'-tert.-butyl-,5'-(1,1,3,3-trimethyl-butyl)-, 5-chloro-3', 5'-di-tert.-butyl-,5-chloro-3'-tert.-butyl-5'methyl-, 3'-sec.-butyl-5'-tert.-butyl-,3'-{α-methylbenzyl}-5'-methyl-, 3'-{α-methylbenzyl}-5'-methyl-5-chloro-,4'-hydroxy-, 4'-methoxy-, 4'-octoxy-, 3',5'-di-tert.-amyl-,3'-methyl-5'-carbomethoxyethyl- or5-chloro-3',5'-di-tert.-amyl-derivative.

2,4-bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, such as, for example,the 6-ethyl-, 6-undecyl- or 6-heptadecyl-derivative.

2-hydroxy-benzophenones, such as, for example, the 4-hydroxy-,4-methoxy-, 4-octoxy-, 4-decyloxy-, 4-dodecyloxy-, 4-benzyloxy-,4,2',4'-trihydroxy- or 2'-hydroxy-4,4'-dimethoxy-derivative.

1,3-bis-(2'-hydroxy-benzoyl)-benzenes, such as for example.1,3-bis-(2'-hydroxy-4'-hexyloxy-benzoyl)-benzene,1,3-bis-(2'-hydroxy-4'-octoxy-benzoyl)-benzene and1,3-bis-(2'-hydroxy-4'-dodecyloxy-benzoyl)-benzene.

Esters of optionally substituted benzoic acids, such as, for example,phenyl salicylate, octylphenyl salicylate, di-benzoylresorcinol,bis-(4-tert.-butylbenzoyl)-resorcinol, benzoyl-resorcinol,3,5-di-tert.-butyl-4-hydroxybenzoic acid 2,4-di-tert.-butyl-phenylester, octadecyl ester or 2-methyl-4,6-di-tert.-butylphenyl ester.

Acrylates, such as, for example, α-cyano-β,β-diphenyl acrylic acid ethylester or isooctyl ester, α-carbomethoxy-cinnamic acid methyl ester,α-cyano-β-methyl-p-methoxy-cinnamic acid methyl ester or butyl ester andN-(β-carbomethoxy-vinyl)-2-methyl-indoline.

Nickel compounds, such as, for example, nickel complexes of2,2'-thio-bis-4-(1,1,3,3-tetramethylbutyl)-phenyl, such as the 1:1 and1:2 complex, optionally with other ligands such as n-butylamine,triethanolamine or N-cyclohexyl-diethanolamine; nickel complexes ofbis-{2-hydroxy-4-(1,1,3,3-tetramethylbutyl)-phenyl}sulphone, such as the2:1 complex, optionally with other ligands such as 2-ethyl-caproic acid;nickel dibutyldithiocarbamate, nickel salts of4-hydroxy-3,5-di-tert.-butylbenzyl-phosphonic acid monoalkyl esters,such as the methyl, ethyl or butyl ester, the nickel complex of(2-hydroxy-4-methyl-phenyl)-undecyl-ketonoxime and nickel3,5-di-tert.-butyl-4-hydroxy-benzoate.

Oxalic acid diamides, such as, for example, 4,4'-dioctyloxyoxanilide,2,2'-dioctyloxy-5,5'-di-tert.-butyl-oxanilide,2,2'-di-dodecyloxy-5,5'-di-tert.-butyl oxanilide,2-ethoxy-5-tertiarybutyl-2'-ethyl-oxanilide,2-ethoxy-2'-ethyl-oxanilide, N,N'-bis-(3-dimethylaminopropyl) oxalamide,mixtures of o- and p-methoxy and o- and p-ethoxy-di-substitutedoxanilides and mixtures of 2-ethoxy-5-tert.-butyl-2'-ethyl-oxanilidewith 2-ethoxy-2'-ethyl-5,4'-di-tert.-butyl-oxanilide.

Sterically hindered amines, such as, for example4-benzoyloxy-2,2,6,6-tetramethylpiperidine,4-stearoyloxy-2,2,6,6-tetramethylpiperidine,bis-(2,2,6,6-tetramethylpiperidyl)-sebacate and3-n-octyl-7,7,9,9-tetramethyl-1,3-triaza-spiro[4,5]decane-2,4-dione.

For exemplification purposes only listed below are compounds of thisinvention which are useful as stabilizers as discussed above.

4-t-butyl-2,6-dimethyl-3-hydroxyphenyl acetic acid

3-(2,4,6-trimethyl-3-hydroxyphenyl)propionic acid

4-(4-t-octyl-2,6-diethyl-3-hydroxyphenyl)-butyric acid

8-(4-cyclohexyl-2,6-dimethyl-3-hydroxyphenyl)-octanoic acid

n-octadecyl 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate

2-(n-octylthio)ethyl 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate

1,6-hexamethylene bis-(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

methyl 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate

neopentanetriyl tris-(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

2-(n-octadecylthio)ethyl4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate

neopentanetetrayltetrakis-(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

3,6-dioxa-1,8-octamethylenebis-(4-t-octyl-2,6-dimethyl-3-hydroxyphenylacetate)

thiodiethylene bis-(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

n-octadecyl 3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate

n-dodecyl 3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate

methyl 3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)-propionate

phenyl 4-t-butyl-2,6-dimethyl-3-hydroxy-phenylacetate

p-t-octylphenyl 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate

neopentyl 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate

n-octyl 2,4,6-trimethyl-3-hydroxyphenylacetate

2-(n-octadecylthio)ethyl3-(4-isopropyl-2,6-dimethyl-3-hydroxyphenyl)propionate

2-ethylhexyl 3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate

2,2-dimethylpropylenebis-[3-(4-cyclohexyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

1,2-propylene bis-[3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

2,2-dimethylpropylenebis-[4-(4-t-butyl-2,6-diethyl-3-hydroxyphenyl)butyrate]

1,8-octamethylenebis-[3-(2,6-di-butyl-4-methyl-3-hydroxyphenyl)propionate]

1-6-hexamethylenebis-[3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

1,12-dodecamethylenebis-[3-(4-cyclopentyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

2,2-dimethyl-1,2,2-butanetriyltris-[3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

1,2,3-propanetriyltris-[3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

2,2-dimethyl-1,2,2-pentanetriyltris(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

neopentanetetrayltetrakis(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

1,2,3-butanetriyl tris-[4-(2,4,6-triisopropyl-3-hydroxyphenyl)butyrate]

o-methylphenyl 3-(4-t-octyl-2,6-dimethyl-3-hydroxyphenyl)propionate

1,2,3,4,5,6-cyclohexanehexaylhexakis-(4-tert-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

n-tetracosanyl 3-(4-tert-octyl-2,6-dimethyl-3-hydroxyphenyl)propionate

cyclohexyl 4-tert-butyl-2,6-dimethyl-3-hydroxyphenylacetate

n-octadecyl (4-tert-butyl-2,6-dimethyl-3-hydroxyphenyl)-α-methylacetate

n-octyl (4-tert-butyl-2,6-dimethyl-3-hydroxyphenyl)-α-n-heptylacetate

neopentanetetrayltetrakis-[3-(4-t-octyl-2,6-dimethyl-3-hydroxyphenyl)propionate]

3-(4-tert-butyl-2,6-dimethyl-3-hydroxyphenyl)-propionamide

4-tert-butyl-2,6-dimethyl-3-hydroxyphenylacetamide

N-methyl-N-n-tetracosanyl-(4-tert-octyl-2,6-dimethyl-3-hydroxyphenyl)acetamide

N-n-octyl-N-phenyl-3-(4-tert-octyl-2,6-dimethyl-3-hydroxyphenyl)propionamide

N-cyclohexyl-3-(4-tert-butyl-2,6-dimethyl-3-hydroxy-phenyl)propionamide

N,N-di-n-butyl-(4-cyclohexyl-2,6-dimethyl-3-hydroxyphenyl)acetamide

N,N',N",N'"-1,4-dimethylcyclohexan-1,1,4,4-tetrayl tetrakis[3-(4-tert-butyl-2,6-dimethyl-3-hydroxyphenyl)-propionamide]

N-o-tolyl-N-methyl-(4-tert-octyl-2,6-dimethyl-3-hydroxyphenyl)acetamide

The following examples are illustrative of the invention, but are notmeant to limit the scope of same. In said examples, parts are by weightunless otherwise indicated and the relationship between parts by weightand parts by volume is as that between grams and cubic centimeters. Thetemperatures are in degrees centigrade.

EXAMPLE 1 6-tert.-Butyl-3-chloromethyl-2,4-dimethylphenol

The compound of this example was made by a procedure described byWegler, et al (Makr. Chem. 9,22(1952)). After crystallization frompetroleum ether, the product was obtained as white crystals melting at45° to 47° C.

EXAMPLE 2 6-tert.-Octyl-3-chloromethyl-2,4-dimethylphenol

The compound of this example was made by a procedure analogous to thecompound of Example 1. After recrystallization from petroleum ether, thedesired compound was isolated as white crystals melting at 80° to 83° C.

EXAMPLE 3 4-tert.-Butyl-2,6-dimethyl-3-hydroxyphenylacetonitrile

To 41 grams of potassium cyanide dispersed in 300 ml ofN,N-dimethylformamide, was slowly added a solution of 97.2 grams of thecompound of Example 1, the reaction temperature rising from 25° to 35°C. The reaction mixture was then heated at 70° to 75° for 71/2 hours.Since a sample analyzed after 7 hours reaction time indicated that someunreacted starting 6-tert.-butyl-3-chloromethyl-2,4-dimethylphenolremained unreacted, an additional 13.7 grams of potassium cyanide wasadded and the reaction mixture heated for an additional 2 hours at 60°to 65° C. The reaction mixture was poured on crushed ice, and wateradded to make the total volume 1.8 liters. The mixture was stirred untilthe ice melted, the aqueous solid dispersion was filtered by suction,and the filtercake washed well with water. The filtercake was taken upin a toluene-benzene mixture, the resulting solution being successivelywashed with water, 6N aqueous hydrochloric acid and dried over anhydroussodium sulfate. After removal of the drying agent by filtration andtreating the clear filtrate with activated charcoal, the solvent wasevaporated at reduced pressures. The resulting residue was allowed tocrystallize from toluene yielding white crystals melting at 134° to139°.

EXAMPLE 4 4-tert.-Octyl-2,6-dimethyl-3-hydroxyphenylacetonitrile

This compound was made substantially in the same manner as described inExample 3 yielding white crystals melting at 109° to 111° aftercrystallization from n-hexane.

EXAMPLE 5 4-tert.-Butyl-2,6-dimethyl-3-hydroxyphenylacetic acid

65.1 grams of the compound of Example 3 was added with stirring to asolution of 36 grams of sodium hydroxide in 40 ml of ethylene glycol and66 ml of water. The reaction mixture became homogeneous at about 116° to117° and was heated at this temperature for two hours. The reactionmixture was cooled by the addition of chopped ice and cold water to thereaction mixture to make a total volume of one liter. After clarifyingthe reaction mixture by filtration, the filtrate was made acid withconcentrated aqueous hydrochloric acid, yielding a white precipitate,which was filtered, washed with cold water and dried. The product wasthen treated with rapid stirring at 50° C with about 800 ml of 6% sodiumbicarbonate solution until carbon dioxide evolution stopped. The turbidsolution was filtered free of a white solid-by-product. (A). Theclarified filtrate was made acid with concentrated hydrochloric acidwhile cooling, and the resulting white precipitate filtered. Afterwashing with hot water and drying the product was obtained as a whitepowder melting at 161° to 165°.

After recrystallizations from toluene and aqueous methanol the meltingpoint was 165° to 167°.

EXAMPLE 6 4-tert.-Butyl-2,6-dimethyl-3-hydroxyphenylacetamide

By-product (A) isolated in Example 5 was crystallized from benzenecontaining a little ethanol yielding the white crystals melting at 194°to 196° C. Carbon, hydrogen, nitrogen microanalysis, infrared spectraand NMR all confirm that this compound is4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetamide.

EXAMPLE 7 4-tert.-Octyl-2,6-dimethyl-3-hydroxyphenylacetic acid

This compound was made in a similar manner to the method disclosed inExample 5 by hydrolyzing4-tert.-octyl-2,6-dimethyl-3-hydroxyphenylacetonitrile with sodiumhydroxide in aqueous ethylene glycol. After crystallization from toluene4-tert.-octyl-2,6-dimethyl-3-hydroxyphenylacetic acid melted at 157° to159° C.

EXAMPLE 8 4-tert.-Octyl-2,6-dimethyl-3-hydroxyphenylacetamide

As in Example 5, a by-product insoluble in aqueous sodium hydroxideformed in Example 7. After crystallization from toluene this by-productwas obtained in pure form and melted at 179° to 181°. (Compound 10)

EXAMPLE 9 n-Octadecyl 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate

10.68 grams of the compound of Example 5, 11.4 grams of n-octadecanoland 0.8 grams of p-toluene sulfonic acid monohydrate were dispersed in150 ml of toluene and heated at reflux for seven hours during which thewater collected by azeotropic distillation was almost equal to thetheory. The reaction mixture was successively washed with water, aqueoussaturated sodium bicarbonate solution, and then with water once againuntil the wash water was neutral. After drying over anhydrous sodiumsulfate and filtering free of the drying agent, the clear filtrate wasevaporated at reduced pressures to yield the desired product as residue.After successive crystallizations from acetonitrile and n-heptane, thedesired compound was isolated as white crystals melting at 57° to 59° C(Compound 1).

Other 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetates made in asimilar manner as Example 9 are shown in Table I.

                  TABLE I                                                         ______________________________________                                        Other 4-tert.-butyl-2,6-dimethyl-3-                                           hydroxyphenylacetates                                                          ##STR13##                                                                    Compound No.                                                                            n     R.sup.3           M.P. ° C.                            ______________________________________                                        2         1     n-C.sub.18 H.sub.37SCH.sub.2 CH.sub.2                                                           53-56                                       3         2     (CH.sub.2).sub.6  133-136                                     ______________________________________                                    

EXAMPLE 10 Methyl 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate

43.4 grams of 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetic acid(Example 5) was added to 200 ml of methanol which had previously beensaturated with hydrogen chloride gas at 15° C yielding a turbid solutionwhich became clear at 30° C. The reaction solution was then heated atreflux for 21/2 hours. The reaction mixture was diluted with about 600ml of an ice-water mixture and stirred until all the ice had melted,yielding a dispersion of the solid methyl ester desired which wasfiltered and washed with water. The filtercake was dissolved in benzeneand successively washed with warm saturated aqueous sodium bicarbonateand water until the wash water was neutral. After drying over anhydroussodium sulfate and filtering free of drying agent and removing thesolvent at reduced pressures, the residue was obtained as a solidmelting at 90° to 93°. Recrystallization from methanol containing alittle water yielded white crystals melting at 90° to 93° (Compound 4).

EXAMPLE 11 Neopentanetriyltris-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate)

16.5 grams of the compound of Example 10, 2.4 grams of1,1,1-trimethylolethane and 9.6 milligrams of lithium hydride wereheated together with stirring in a dry nitrogen atmosphere at 140° to145° for 23/4 hours and at 150° to 155° for 13/4 hours at oneatmosphere. The reaction melt was then heated with stirring at 155° for6 hours at 20 mm Hg. pressure. After addition of about 0.1 to 0.2 gramsof glacial acetic acid to neutralize the lithium catalyst, the glassyreaction mixture was dissolved in 200 ml of warm benzene containingabout 25 ml of chloroform, clarified by filtration and the resultingclear solution successively washed with water, aqueous 3N hydrochloricacid, water, 2N aqueous sodium hydroxide and finally with water againuntil the wash water was neutral. After drying over anhydrous sodiumsulfate and filtering free of drying agent, the clear filtrate wasconcentrated at reduced pressures to yield a glassy residue. Successivecrystallizations from carbon tetrachloride and acetonitrile yieldedwhite crystals melting at 165° to 167° (Compound 5).

2,2-Dimethylpropylenebis(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate) is prepared in asimilar manner as the compound of Example 11 by substituting2,2-dimethyl-1,3-propanediol for 1,1,1-trimethylolethane.

EXAMPLE 12 Neopentanetetrayltetrakis-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate

15.5 grams of the compound of Example 10, 1.90 grams of pentaerythritol,6.7 milligrams of lithium hydride and 1.3 ml of dimethyl sulfoxide weremelted and heated together in a dry nitrogen atmosphere at 135° to 140°for 2 hours, 140° to 145° for 1 hour and 145° to 150° for another 2hours. The reaction mixture was then heated at 20 mm Hg. nitrogenpressure at 150° to 165° for 16 hours. The vacuum was then released withnitrogen and an additional 6 milligrams of lithium hydride wasintroduced and heating continued for an additional 24 hours at 20 mm Hg.nitrogen pressure at 160° to 165°. The glassy reaction product wasdissolved in 100 ml of warm benzene containing 0.5 ml of glacial aceticacid and the solution washed successively with water, 3N aqueoushydrochloric acid, 2N aqueous sodium hydroxide and finally with wateruntil the wash water was neutral. After drying over anhydrous sodiumsulfate and removing the drying agent by filtration, the clear filtratewas freed of solvent by distillation at reduced pressures yielding abrown glassy residue. The glassy residue was crystallized twice fromcarbon tetrachloride. The desired product was isolated in pure form byelution column chromatography using silica gel G (Grace) using a solventmixture of 50 parts by volume of benzene and 50 parts by volume ofhexane as eluant, the purified product being found after thebenzene-hexane eluant was evaporated to dryness at reduced pressures.After crystallization from carbon tetrachloride, the desired product wasobtained as white crystals melting at 153° to 155° (Compound 6).

Thiodiethylene bis-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate)is made by an analogous rocedure as the product of Example 12 bysubstituting thiodiglycol for pentaerythritol.

EXAMPLE 13 3,6-Dioxa-1,8-octamethylenebis-(4-tert.-octyl-2,6-dimethyl-3-hydroxyphenylacetate)

9.7 grams of 4-tert.-octyl-2,6-dimethyl-4-hydroxyphenylacetic acid, 2,2grams of triethyleneglycol and 0.57 grams of p-toluenesulfonic acidmonohydrate were dispersed together in 150 ml of toluene and heated atreflux for 15 hours, the water of reaction being removed by azeotropicdistillation. After washing the toluene reaction mixture successivelywith water, 2N aqueous sodium hydroxide and again with water andremoving the solvent by distillation in vacuum, the residue wassuccessively crystallized from acetonitrile and nitromethane yieldingwhite crystals melting at 114° to 120° (Compound 7).

EXAMPLE 14 Diethyl 4-tert.-butyl-2,6-dimethyl-3-hydroxybenzylmalonate

1.15 grams of small pieces of sodium and 1.8 grams of diethyl malonatein 80 ml of dry heptane were heated together at 55° to 60° for 1 hourand then at reflux for 21/2 hours forming the sodium salt of diethylmalonate as a white dispersion in n-heptane. To the above whitedispersion was added dropwise over a period of 20 minutes at 25° to 26°11.45 grams of 6-tert.-butyl-3-chloromethyl-2,4-dimethylphenol dissolvedin 25 ml of dry heptane, the reaction mixture being heated at reflux for81/2 hours. After addition of about 100 ml of ether to the reactionmixture and washing the resulting turbid solution successively withwater, 6N aqueous hydrochloric acid and again with water to pH5, theclear solution was dried over anhydrous sulfate, and the solvent wasremoved by distillation in vacuum. The residue was crystallized frompetroleum ether yielding the product as white crystals melting at 56° to59°. (Compound 11)

EXAMPLE 15 Di-n-octadecyl4-tert.-butyl-2,6-dimethyl-3-hydroxybenzylmalonate

6.3 grams of the compound of Example 14, 9.8 grams of n-octadecanol and0.890 grams of dibutyltin oxide were heated together as a melt at 130°to 140° for 3 hours, 140° to 150° for 1 hour in a rapid stream ofnitrogen to remove the ethanol of reaction. Finally the reaction mixturewas heated at 145° to 150° at 20 to 25 mm Hg. pressure for 2 hours. Thesolidified melt was dissolved in 100 ml of toluene and successivelywashed with water, aqueous 6N hydrochloric acid, water and saturatedsodium bicarbonate solution, the toluene solution being dried overanhydrous sodium sulfate. After removal of the toluene by distillationat reduced pressures and purification by elution chomatography overactivated alumina (Woelm, Activity II), the residue was crystallizedfrom hexane yielding white crystals melting at 72° to 74°. (Compound 12)

EXAMPLE 16 4-tert.-Butyl-2,6-dimethyl-3-hydroxybenzylmalonic acid

35 grams of the compound of Example 14 was dissolved in 125 ml ofmethanol together with 12.3 grams of sodium hydroxide dissolved in 50 mlof water and heated at reflux for 6 hours. After removal of most of themethanol by distillation at reduced pressure, 300 ml of water was addedand stirred to yield a turbid solution which was clarified byfiltration. The clear filtrate was extracted with ether, and the etherextract washed with water and dried over anhydrous sodium sulfate. Afterremoval of the ether by distillation at reduced pressure, the glassyresidue was crystallized from 1,2-dichloroethane yielding white crystalsmelting at 174°.

EXAMPLE 17 3-(4-tert.-Butyl-2,6-dimethyl-3-hydroxyphenyl)propionic acid

17.9 grams of the compound of Example 16 was stirred together with whiteoil at 165° to 180° for two hours until little CO₂ evolution could bedetected. The reaction mixture was cooled to 50° and stirred thoroughlytogether with 5.2 grams of sodium bicarbonate dissolved in 100 ml ofwater until no foaming took place and all solids had dissolved. Thereaction mixture was diluted with 50 ml of n-hexane and the upperorganic phase separated from the lower aqueous phase. The organic phasewas washed with water, the wash water being combined with the aqueousphase. The combined aqueous phase was then washed with n-hexane,clarified by filtration through filtercel, and added dropwise to about150 ml of cold 6N aqueous hydrochloric acid so that a granular off-whiteprecipitate was obtained. The product was used as such after drying inthe vacuum oven at 60° and 3mm Hg. overnight.

EXAMPLE 18 Methyl3-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate

13.6 grams of the product of Example 17 was dissolved in 200 ml ofmethanol saturated with anhydrous hydrogen chloride gas at 15° C, heatedat reflux (60° to 71°) for 3 hours, and then concentrated to one-thirdvolume by distilling off solvent at reduced pressure. After pouring theconcentrate on an icewater mixture while stirring, the resultingcrystalline precipitate was taken up in toluene, the toluene solutionbeing successively washed with water, aqeuous 2N sodium hydroxide,saturated sodium chloride solution and water until the pH of the washwater was neutral. After drying over anhydrous sodium sulfate andremoval of the solvent by distillation at reduced pressure, the residuewas ground to a powder and freed of colored impurities by triturationwith petroleum ether. Crystallization from n-heptane yielded the productas white crystals melting at 108° to 110° (Compound 8).

EXAMPLE 19 n-Octadecyl3-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate

6.4 grams of the compound of Example 18, 6.24 grams of n-octadecanol and9.6 milligrams of lithium hydride were melted together under nitrogen at110° C and then heated with stirring at 125° to 135° for 2 hours, at140° to 155° for 11/2 hours and at 155° for 45 minutes at 20 mm Hg.pressure. The reaction mixture was dissolved in 200 ml of toluenecontaining 1 ml of acetic acid, the toluene solution being thensuccessively washed with aqueous 6N hydrochloric acid, water, aqueous 2Nsodium hydroxide, saturated sodium chloride and water until pH5. Afterdrying the toluene solution over sodium sulfate and removing the tolueneby distillation at reduced pressure, the residue was crystallized frommethanol yielding white crystals melting at 49° to 51° (Compound 9).

n-Dodecyl 3-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate isobtained by using the procedure of Example 19 by substitutingn-dodecanol for n-octadecanol.

EXAMPLE 20 4-tert.-Butyl-2,6-dimethyl-3-hydroxyphenylacetyl chloride

47.2 g (0.20 moles) of 4-t-butyl-2,6-dimethyl-3-hydroxyphenyl aceticacid, and 0.4 ml of dry N,N-dimethylformamide are dispersed in 325 ml ofdry benzene. To this slurry was added dropwise with stirring under anitrogen atmosphere 28.5 g (17.5 ml, 0.24 moles) of thionyl chloride atambient temperature. The reaction mixture was allowed to stir for 16hours, then evaporated under reduced pressure, yielding anorange-colored solid, which proved by analysis to be the desired acidchloride. The residue was dissolved in 500 ml of benzene, analyzed forchloride ion and used for subsequent reactions in solution.

EXAMPLE 21 phenyl 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate

Triethylamine is added dropwise to an equimolar mixture of phenol andthe compound of Example 20 in benzene at room temperature and allowed toreact at ambient temperature. After filtration of the triethylaminehydrochloride the product is recovered by removing the solvent bydistillation.

p-tert.-Octylphenyl 4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetate ismade in analogous manner by substituting p-tert.-octylphenol for phenolin the above procedure.

EXAMPLE 22N-Methyl-N-n-octadecyl-4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetamide

A solution of 10.19 gms of4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetyl chloride in 100 ml ofbenzene was added dropwise at 10° to 12° with stirring over a 40 minuteperiod to a solution in 200 ml of dry benzene of 22.64 (0.08 moles) ofN-methyl-N-n-octadecylamine and stirring overnight at room temperature.After filtering free of the precipitated solid, the filtrate wasevaporated under reduced pressure and the residue recrystallized fromheptane, yielding white crystals, m.p. 115° to 116.5° of the desiredmaterial (Compound 13).

EXAMPLE 23 N,N-Dimethyl4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetamide

This compound was prepared by a similar procedure to that of Example 22by substituting anhydrous dimethylamine for N-methyl-N-octadecylamine.After crystallization from benzene the product was obtained as whitecrystals melting at 191° to 194° (Compound 14).

EXAMPLE 24N,N'-Bis(4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetyl)piperazine

To a solution of 3.45 g (0.04 moles) of piperazine and 8.5 g (0.084moles) of triethylamine in 100 ml of dry benzene was added dropwise withstirring at 10° to 12° over a period of 40 minutes a solution of 20.38 g(0.08 moles) of 4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetyl chloride in200 ml of benzene. The reaction mixture was allowed to stir overnight atroom temperature then was heated at reflux for two hours. The reactionmixture was then cooled, filtered with suction and the collected solidswashed well with water. The water insoluble material was recrystallizedfrom a solvent mixture of chloroform/N,N-dimethylformamide yieldingwhite crystals, m.p. 305° to 310° after drying, of the desired material(Compound 15).

EXAMPLE 25 N-n-Octadecyl-4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetamide

21 g (0.084 moles) of methyl4-t-butyl-2,6-dimethyl-3-hydroxyphenylacetate and 22.6 g (0.084 moles)of n-octadecylamine were heated together over a period of 3 hours undera nitrogen atmosphere to 185° to 195° C. The reaction mixture was thenheld at this temperature until the expected amount of methanol wasobtained by distillation. The reaction product was washed with heptane,dissolved in benzene, and filtered through a layer of silica gel. Afterevaporation of the benzene solution at reduced pressure, the product wasrecrystallized from heptane, yielding the desired material as whitecrystals, m.p. 88° to 94° C (Compound 16).

EXAMPLE 26 N-n-Octyl-4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetamide

This product was made by an essentially similar procedure as describedin Example 25 by substituting n-octylamine for n-octadecylamine. Theproduct is obtained as white crystals melting at 101° to 104° aftercrystallization from n-heptane (Compound 17).

EXAMPLE 27N,N'-Bis-(4-tert.-butyl-2,6-dimethyl-3-hydroxyphenylacetyl)hexamethylenediamine

This compound was made by an analogous procedure to Example 25 bysubstituting 0.5 molar equivalent of hexamethylenediamine forn-octadecylamine. After crystallization from a solvent mixture ofacetone/cyclohexane the product is obtained as white crystals melting at202° to 204° (Compound 18).

Unstabilized polypropylene powder (Hercules Profax 6501) was thoroughlyblended with 0.2% by weight of the indicated stabilizer compound. Alsoprepared were samples of polypropylene containing 0.1% by weight of thesame stabilizer and 0.3% by weight of DSTDP (distearylβ-thiodipropionate). The blended materials were then milled on atwo-roll mill at 182° C for 10 minutes, after which time the stabilizedpolypropylene was sheeted from the mill and allowed to cool.

The milled polypropylene sheets were then cut into pieces and pressedfor 7 minutes on a hydraulic press at 218° C, 19.25 Kg/cm² pressure. Theresulting plaques of 0.635 mm thickness were tested for resistance toaccelerated aging in a forced draft oven at 150° C.

When the plaques showed the first signs of decomposition (e.g., crackingor brown edges) they were considered to have failed. The results areshown in Table II, Table III and Table IV.

                  TABLE II                                                        ______________________________________                                        OVEN AGING OF ALKYLSUBSTITUTED                                                HYDROXYPHENYLALKANOATES                                                       IN POLYPROPYLENE                                                              ______________________________________                                        Ex.                                                                           No.   Percent Stabilizer    Hours to Failure                                  ______________________________________                                        27   No Stabilizer          3                                                 28   0.2% Compound 4        < 20                                              29   0.1% Compound 4 + 0.3% DSTDP                                                                         160                                               30   0.2% Compound 1        75                                                31   0.1% Compound 1 + 0.3% DSTDP                                                                         635                                               32   0.2% Compound 2        810                                               33   0.1% Compound 2 + 0.3% DSTDP                                                                         1440                                              34   0.2% Compound 3        245                                               35   0.1% Compound 3 + 0.3% DSTDP                                                                         1320                                              36   0.2% Compound 5        360                                               37   0.1% Compound 5 + 0.3% DSTDP                                                                         1680                                              38   0.2% Compound 6        340                                               39   0.1% Compound 6 + 0.3% DSTDP                                                                         1620                                              40   0.2% Compound 7        260                                               41   0.1% Compound 7 + 0.3% DSTDP                                                                         1140                                              42   0.2% Compound 8        < 20                                              43   0.1% Compound 8 + 0.3% DSTDP                                                                         135                                               44   0.2% Compound 9        130                                               45   0.1% Compound 9 + 0.3% DSTDP                                                                         725                                               ______________________________________                                    

Correspondingly good stabilization is achieved when the stabilizerconcentration is varied from 0.01 to 2%.

The stabilizers are particularly effective in the presence of a thioester co-stabilizer such as DSTDP.

                  TABLE III                                                       ______________________________________                                        OVEN AGING OF ALKYLSUBSTITUTED                                                HYDROXYBENZYLMALONATE                                                         STABILIZERS IN POLYPROPYLENE                                                  ______________________________________                                        Ex.                                                                           No.   Percent Stabilizer    Hours to Failure                                  ______________________________________                                        46   No Stabilizer          3                                                 47   0.2% Compound 11       < 20                                              48   0.1% Compound 11 + 0.3% DSTDP                                                                        270                                               49   0.2% Compound 12       200                                               50   0.1% Compound 12 + 0.3% DSTDP                                                                        2075                                              ______________________________________                                    

Correspondingly good stabilization is achieved when the stabilizerconcentration is varied from 0.01 to 2%.

                  TABLE IV                                                        ______________________________________                                        OVEN AGING OF AMIDE STABILIZER IN                                             POLYPROPYLENE                                                                 ______________________________________                                        Ex.                                                                           No.   Percent Stabilizer    Hours to Failure                                  ______________________________________                                        51   No Stabilizer          3                                                 52   0.2% Compound 10       < 20                                              53   0.1% Compound 10 + 0.3% DSTDP                                                                        165                                               54   0.2% Compound 13       275                                               55   0.1% Compound 13 + 0.3 DSTDP                                                                         980                                               56   0.2% Compound 14       < 20                                              57   0.1% Compound 14 + 0.3 DSTDP                                                                         145                                               58   0.2% Compound 15       120                                               59   0.1% Compound 15 + 0.3 DSTDP                                                                         1165                                              60   0.2% Compound 16       130                                               61   0.1% Compound 16 + 0.3 DSTDP                                                                         535                                               62   0.2% Compound 17       < 20                                              63   0.1% Compound 17 + 0.3 DSTDP                                                                         260                                               64   0.2% Compound 18       310                                               65   0.1% Compound 18 + 0.3 DSTDP                                                                         625                                               ______________________________________                                    

Correspondingly good stabilization is achieved when the stabilizerconcentration is varied from 0.01 to 2%.

The stabilizers are particularly effective in the presence of a thioester co-stabilizer such as DSTDP.

EXAMPLE 66

Pellets (500 g) of unstabilized nylon-6,6 (Zytel 101, DuPont) are placedin a Kitchen Aid Mixer. With mixing a solution of 0.5% (based on theweight of nylon) of methyl 3-(2,4,6-trimethyl-3-hydroxyphenyl)propionatein 20 ml of methylene chloride is added slowly. Sodium hypophosphite(0.5 gm 0.1%) is dissolved in 20 ml of water and added slowly withmixing to the nylon pellets after the antioxidant solution has beenadded and most of the methylene chloride has evaporated. The stabilizedpellets are dried at 80° C at <1 mm Hg for 4 hours.

The polyamide formulation is extruded at 315.6° C through at 0.625 cmdie into a rod which is water cooled and chopped into pellets. A 1.905cm Brabender extruder, equipped with a nylon screw, is used. The pelletsare dried at 80° C at <1 mm for 4 hours.

The dried pellets are compression molded into 0.127 mm thick film bypressing at 290° C for 4 minutes at 57.75 Kg/cm². The films are ovenaged at 150° C in a forced draft oven and samples are removedperiodically. The specific viscosity of the samples are determined usinga 1% formic acid solution at 25° C. The sample stabilized with the abovenoted stabilizer required longer aging time to reduce its viscosity byone-half than the unstabilized sample.

EXAMPLE 67

Unstabilized high impact polystyrene resin is dry blended with 0.01% byweight of the resin of methyl8-(4-cyclohexyl-2,6-dimethyl-3-hydroxyphenyl)octanoate. The resin isthen extrusion compounded on a 2.54 cm 24/1=L/D extruder, melttemperature 260° C and then pressed for 7 minutes at a temperature of163° C and a pressure of 140 Kg/cm² into a sheet of uniform thickness of2.54 mm. The sheets are then cut into plaques of 5.08 cm × 5.08 cm. Theplaques are then oven aged at 80° C and color measurements madeperiodically using a Hunter Color Difference Meter Model D25. Thepolystyrene samples stabilized with the above stabilizer develops theundesirable yellow discoloration substantially later than the time thatsuch discoloration occurred in the unstabilized samples.

EXAMPLE 68

Unstabilized linear polyethylene (HiFax 4401) is solvent blended inmethylene chloride with 0.5% by weight of the substrate of n-octadecyl3-(4-t-butyl-2,6-di-methyl-3-hydroxyphenyl)propionate and then vacuumdried. The resin is then extruded at 232.2° C using a 1.905 cm extruderhaving a 24:1 L/D ratio. The melt flow rate of a sample of the resin isdetermined after each extrusion according to ASTM test D-1238.Polyethylene stabilized with above compound is found to undergo lesschange in the melt flow rate than the unstabilized polyethylene.

EXAMPLE 69

A quantity of SBR emulsion containing 100 g of rubber (500 ml of a 20%SBR emulsion obtained commercially from Texas U.S. as Synpol 1500)previously stored under nitrogen, is placed in a beaker and stirredvigorously. The pH of the emulsion is adjusted to 10.5 with a 0.5N NaOHsolution.

To the emulsion is added 50 ml of 25% NaCl solution. A 6% NaCl solutionadjusted with hydrochloric acid to a pH 1.5 is added in a thin streamwith vigorous stirring. When pH 6.5 is reached, the rubber begins tocoagulate and the addition is slowed down in order to maintain uniformagitation. The addition of the acidic 6% NaCl solution is terminatedwhen a pH 3.5 is reached. The coagulated crumb-rubber slurry at pH 3.5is stirred for 1/2 hour.

The coagulated rubber is isolated by filtration through cheese cloth,and rinsed with distilled water. After three subsequent washings withfresh distilled water, the coagulated rubber is dried, first at 25 mm Hgand finally to constant weight under high vacuum (<1 mm) at 40° to 45°C.

The dried rubber (25 g) is heated under nitrogen at 125° C in aBrabender mixer and to this is added with mixing 0.1%2-(n-octadecylthio)ethyl3(4-isopropyl-2,6-dimethyl-3-hydroxyphenyl)propionate.

Portion of the rubber are oven aged at 100° C. At various intervals gelcontent is determined on the rubber. The rubber stabilized with theabove compound shows much less gel formation than the unstabilizedsample.

EXAMPLE 70

To 50 g of polyacetal resin containing 0.1% of an acid scavenger,dicyandiamide, is added 0.2% by weight of 2-ethylhexyl3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate and milled for 7minutes at 200° C in a Brabender Plasti-recorder. The milled formulationis subsequently pressed into a 1.016 mm sheet at 215° C at 24.5 Kg/cm²for 90 seconds then cooled quickly in a cold press at 24.5 Kg/cm². Thestabilized sheets are then remolded for 2 minutes at contact pressureand for 3 minutes at 21 Kg/cm² at 215° C to give plaques 3.81 cm × 5.715cm × 3.175 mm.

The plaques are aged in the oven at 60° C and the weight loss of thespecimen is determined periodically until a 4% weight loss is reached.The stabilized sample takes a much longer time to reach this 4% weightloss than does the unstabilized sample.

EXAMPLE 71

Unstabilized, thoroughly dried polyethylene terephthalate chips are dryblended with 1.0% of 1,2-propylenebis[3-(4-cyclohexyl-2,6-dimethyl-3-hydroxyphenyl)propionate]. 60/10denier multifilament is melt spun at a melt temperature of 290° C. andcold oriented 3 to 1. The oriented fibers are wound into skeins and ovenaged at 140° C. The stabilized material exhibits greater retention oftensile strength after 24 hours than the unstabilized material.

EXAMPLE 72

A stabilized high temperature lubricating oil is prepared byincorporating 2% by weight of 2,2-dimethyl-1,2,2-butanetriyltris-[3-(4-t-butyl-2,6-dimethyl-3-hydroxyphenyl)propionate] to thelubricant which comprises diisoamyl adipate. The stabilized compositionis compared with the unstabilized lubricant by heating at 175° C in thepresence of air and metallic catalysts according to the test methoddescribed in Military Specification Mil-I-7808c. After 72 hours, theblank containing no stabilizer contains more sludge and has a greaterviscosity than the stabilized lubricant.

What is claimed is:
 1. A compound having the formula ##STR14## wherein R is a branched alkyl of 3 to 8 carbon atoms,R¹ and R² are alkyl of 1 to 3 carbon atoms, and A is a straight chain alkylene of 1 to 3 carbon atoms.
 2. A compound of claim 1 wherein R is a branched chain alkyl and R¹ and R² are straight chain alkyl.
 3. A compound of claim 1 wherein R is tert-alkyl and R¹ and R² are methyl.
 4. The compound of claim 1, N,N'-bis(4-tert.butyl-2,6-dimethyl-3-hydroxyphenylacetyl)piperazine. 